Study on the frequency spectrums of acoustic emission PD signals in XLPE cable accessories

In this paper, four 110 kV prefabricated cable joints models containing four kinds of known representative insulation defects were designed. The models can simulate some typical PD phenomena, such as sliding discharge, floating discharge, cavity discharge and protrusion discharge. Based on them, type frequency spectrums of AE PD signals in XLPE cable joints were studied. The investigation indicated that the main frequency component of AE PD signals for XLPE cable is less than 400 kHz; the attenuation of higher frequency component is very fast; the energy is relatively centralized in 50~250 kHz; the sensitivity in this band is very high; the characteristics of different PD models are apparently dissimilar from each other. The obtained results provided basis for future investigation on PD pattern identification.